1. Field of the Invention
The present invention relates to a head-mounted picture display device, or more particularly, to a head-mounted picture display device having a picture display system stowed in a housing body.
2. Description of the Related Art
A head-mounted picture display device designed to be mounted on the observer""s head in a manner which will partly mask the observer""s face gains advantages over other portable picture display devices. Specifically, the head-mounted picture display device enables a person to view a picture while having his/her hands free. Moreover, since the head-mounted picture display device can offer a field of view analogous to one provided by viewing a large screen, a picture can be viewed with a sense of reality and impact.
In this kind of head-mounted picture display device, extraneous light is reflected from emission surfaces for emitting picture beams. Images from the background of the device may therefore be projected to hinder viewing of a picture. Various proposals have been made address this drawback in the past.
A glasses type picture display device is disclosed as an example of such head-mounted picture display devices in Japanese Unexamined Patent Publication No. 6-141259. Pictures produced by a pair of picture display means incorporated in a main unit are enlarged by a pair of eyepieces and projected on the retinas of the user""s eyes. A pair of eyepiece windows is created to be opposed to the pair of eyepieces in the main unit. Transparent window plates are fitted in the eyepiece windows. The transparent window plates are tilted at a predetermined angle with respect to the eyepieces. Due to the tilted transparent window plates, reflection of unnecessary external light surrounding a picture is prevented so as effort to make the picture on a product panel easier to see.
Moreover, Japanese Unexamined Patent Publication No. 8-136852 has disclosed another example of an optical device which includes an eyepiece optical system for transmitting an image to an observer and reflecting mirrors for reflecting light that produces an image. The eyepiece optical system has sheet polarizers or optical absorption filters interposed between the reflecting mirrors and the observer""s eyes. Occurrence of glares or ghost images caused by leakage light can be prevented, thus enabling viewing of a good image.
However, in the foregoing technological examples, special consideration has not been given to the relationship between the transparent plates in the portions to which beams producing the pictures are irradiated and the housing body accommodating the transparent plates. Complex dies may therefore be needed for molding the housing body or a plurality of members must be assembled to construct the housing body. There is thus a probability of inviting an increase in cost.
Furthermore, there is a possibility that the transparent plates mounted in the housing body during the process of manufacturing may be dismounted or displaced until they are secured using an adhesive or the like. Every time the transparent plates are dismounted or displaced, they must be remounted or repositioned. This leads to degraded work efficiency.
Moreover, the transparent plates are designed to be larger so that they can easily pass the beams forming the pictures and emanating from optical elements such as prisms. Consequently, the large area of the transparent plates are susceptible to having a background or the like being readily be projected to the surrounding areas, and may cause the design of the head-mounted picture display device to be undesiredly bulky.
An object of the present invention is to provide a low-cost head-mounted picture display device in which transparent plates can be properly united with a housing body.
Briefly, the present invention provides a head-mounted picture display device comprising a picture display system and a housing body. The picture display system includes picture display members for producing pictures according to a supplied video signal, and optical elements for introducing beams which transmit the pictures produced by the picture display members to the observer""s eyes. The housing body accommodates the picture display system. The housing body has light transmitting portions formed by covering through, which the beams emitted from the optical elements are propagated to the observer""s eyes, with transparent plates. The transparent plates are fitted in the apertures in such a position that the normal vectors to the main surfaces of the transparent plates will intersect the plane at which the front and back members of the housing body are joined.
Moreover, the present invention provides a head-mounted picture display device comprising a picture display system and a housing body as above, and further in which by the transparent plates main surfaces will extend along abutment planes surrounding the apertures of the housing body.
Furthermore, the present invention provides a head-mounted picture display device comprising a picture display system and a housing body as described above and wherein the transparent plates are fitted in the apertures so that the center positions thereof will not be aligned with the ray axes of the beams emitted from the optical elements.
The present invention provides a head-mounted picture display device comprising picture display members, optical elements, and window frame members. The picture display members produce pictures according to a supplied video signal. The optical elements introduce beams, which transmit the pictures produced by the picture display members towards the observer""s eyes. The window frame members restrict the viewable range in which the emitted beams can propagate from the optical elements towards the observer""s eyes, and thus limits a view zone. The window frame members have the center positions of the light transmitting areas thereof set so that the center positions will not be aligned with the ray axes of the beams emitted from the optical elements.
These objects and advantages of the present invention will become further apparent from the following detailed explanation.